1. Field of Invention
The invention relates to a switch, in particular a brake light switch for an automobile with an axially displaceable plunger for the actuation of a make-and-break contact of the switch, whereby the plunger protrudes into a bore of a locking organ, i.e., member, which can be rotated relative around the plunger between an adjustment position and a locking position. The plunger and the locking organ have complimentary locking elements that are strung together in a comb-like manner in axial direction. The plunger can be axially adjusted in the adjustment position relative to the locking organ, and the locking organ can be rotated into the locking position in which the locking elements engage into each other in a radial overlapping manner and are fixed in the axial direction after the axial adjustment process has been completed.
2. Description of the Prior Art
Such a switch is known from EP 0840335 A2, for example. According to it, the locking organ is embodied as a slide that glides fixed into the axial direction inside of the switch housing, which carries a contact unit that can make contact with contact components that are seated stationary within the housing. The plunger is supported displaceable in longitudinal direction in the housing and can be rotated by means of a key-like actuating element, in which it is supported stationary and displaceable in longitudinal direction. The actuating element has an actuating finger protruding laterally, which protrudes into one of the recess areas of a mounting port that is embodied in a base component within the pedal space of the automobile.
The actuating finger overlaps the laterally protruding retaining fingers of the housing in the adjustment position of the plunger.
The retaining fingers are embodied corresponding to the recess areas, and can be plugged in through the same, whereby the actuating finger protrudes into the recess area. Once the switch is attached to the base component, the exterior surface end of the plunger that is pushed out of the housing to the maximum degree abuts the spring-loaded pedal lever in its initial position. Due to the fact that the locking element and the ribs are not engaged in the adjustment position, and because a tension spring of the plunger is weaker than the spring force of the pedal lever, the plunger is pushed into the housing and into the slide in a telescoping manner until the front of the housing abuts the base component, and the retaining fingers are completely pushed through the mounting port.
The housing is now rotated around its longitudinal axis so that the retaining fingers engage into the base component in the manner of a bayonet catch, thus fixing the switch. During this rotating motion the actuating finger is retained in the recess area, and thereby rotated in relation to the housing. This rotation is transferred to the actuating component, and therefore to the plunger, which is thereby rotated in relation to the slide that is stationary within the housing. Its groove-type locking elements are rotated to the angular segment of the rib-type locking element and axially fixed, which also causes the slide to be axially fixed onto the plunger. If the brake pedal is now pushed down, the plunger is released, and the slide is displaced against the contact elements together with the contact unit under the force of a compression spring, which causes the contact to be closed and the brake light to turn on.
Because the plunger is especially exposed it may happen that its rotation position is changed before or during the insertion into the mounting port due to unintentional exterior influences, which causes the engagement of the locking elements between the plunger and the slide in an axially false position. However, if a solution is chosen in which the plunger is stationary and the slide is rotated, the powerful frictionally engaging compression spring can be submitted to torsion, thereby exerting a rebound that compromises the safety of the locking position.
The invention is based on the task of increasing the functional safety of the switch